Question

我是新手，我试图从头文件中发出信号并将其捕获到我的主类中。为此已经写了这个头文件：-

KeyBoard.h:-

#ifndef KEYBOARD_H
#define KEYBOARD_H

#include <QObject>
#include <QDebug>

class KeyBoard : public QObject{
    Q_OBJECT
public:
    KeyBoard();
    int keyboard_update(QByteArray recieved_key);
signals:
    void keyboard_respoense(QString message);
private:
    int level;
    int sub_level;

};

#endif

和

KeyBoard.cpp:-

#include "KeyBoard.h"

KeyBoard::KeyBoard()
{
    level = 0;
    sub_level = 0;
}

int KeyBoard::keyboard_update(QByteArray recieved_key)
{
    qDebug() << "recieved key == " << recieved_key;
        qDebug() << "button  == " << recieved_key.at(8);    
    emit keyboard_respoense("PRESS ENTER TO SELECT TRAIN"); 

    return 1;
}

在我的主班上，我正在捕捉这样的信号：-

keyboard = new KeyBoard;
connect(keyboard,SIGNAL(keyboard_respoense(QString message)),this,SLOT(send_to_MBU(QString message)));

但是当我使用此行调用keyboard_update函数时：-

keyboard->keyboard_update(raw_data_MBU_qb);

它进入keyboard_update（）函数，但从不发出信号，或者可能是发出信号，但我无法捕获它。所以，请告诉我在这里我到底想念什么。

Answer 1

在connect函数中，无需提及参数名称。只需声明参数类型即可。像这样连接：-

connect(keyboard,SIGNAL(keyboard_respoense(QString)),this,SLOT(send_to_MBU(QString)));

Answer 2

要让编译器为您提供帮助，请更新至C ++ 11或更高版本并编写 connect（键盘，＆Keyboard :: Keyboard_respoense，this，＆SnakeCaseClass：send_to_MBU）;

Qt不发射信号

2 个答案: